Rhythmic Noise

[David53]

Just became aware of a new noise. When driving there is a faint but steady rhythmic sound, best way I can describe is a kind of "wup-wup-wup-wup". It sounds a little like a worn wheel bearing not as deep. When you slip out of gear and coast the noise stops. Most evident when accelerating in top gear. So evidently it is somewhere in the drive train. Anyone have an idea what this could be? There is no vibration associated with it.

[mike.perry]

Brake shoes rubbing?

[David53]

Don't think so Mike - it stops when you slip out of gear

[bmcecosse]

Prop shaft U joints or bolts loose?

[David53]

Yes thought of that too Roy - but the prop shaft is still spinning when out of gear isn't it?

[taupe]

Yes its still spinning but the load is off it, so worth checking.

[bmcecosse]

Exactly - spinning, but not carrying any torque........

[David53]

Ahh. Yes I will check the UV's today. It does sound rather like propshaft but assumed it should still be evident in coasting mode. Thanks

[David53]

Well the rear UV joint has a small amount of play in one direction, tight in the other direction. Only a small amount though. So doubt this would cause much noise? However, while under there I checked diff oil and had to squirt 5 syringes full of HP90 in there. So possibly a low oil problem? Although it wasn't a whine, more of a rhythmic noise....

Also how much free play is acceptable in the diff? Rear wheels can be turned about 3-4 inches before the slack takes up and propshaft turns

[bmcecosse]

That sounds about right. Did you grease the prop shaft joints while under there?

[MarkyB]

the rear UV joint has a small amount of play

It's on it's way out then, if you can find play with hand pressure it will be much worse with engine torque.

[David53]

OK, sounds loike new UV's needed then. ESM has them for only 6 Pounds - prob worth doing both ends. Is it a hard job? I presume you just take off the circlips and knock the joints out?

And yes Roy, gave them a good greasing while there

[bmcecosse]

Did the greasing not help the noise any? It's not as simple as you make it sound - but basically - yes that's what you do. It will be a standard size joint - you may get the bits locally. I assume you have checked the tyres for bulges and/or tread coming away from the carcase ?

[David53]

To be honest ran out of time to road test. Going on a trip next weekend so will check then. Tyres are all fine, have only had 5,000 miles from new. And if this was the cause it would still be evident coasting wouldn't it?

[bmcecosse]

Maybe you have flat spotted them braking hard for a tight corner.......

[David53]

In an 803??

[David53]

Ok it's definitely the back UJ on the propshaft. Is more evident when under load, especially pulling up a hill in top gear. Not a major noise yet but I'm sure it will deteriorate quickly. Anyone replaced the UJ's before? Any tips?

[mogbob]

A Google video search "Universal joinr replacement " will come up with a number of hits.
Rear wheels up on ramps, axle stands for good access, chock fornt wheels well.
Make sure you mark the flanges...scribe with a sharp instrument, so that the propshaft can go back with the same orientation. failure to do this may mean result in an inbalance which sets up vibration.
A drip tray to catch the oil drips from the gearbox, a new nuts & bolts as required,Clean out the circlip area well, wire brush and a squirt of WD40 or something similar.Tools shown in the video clips but circlips pliers are useful.(You can file down an old pair of thin nose pliers if you are desparate ).
Keep it all spotlessly clean, new UJs should be greased already.
If the rear gearbox tailshaft oil seal needs replacing...now...would be a good time to replace, whilst the propshaft is off and out of your way.They don't cost much and solve an oil drip problem.

Bob

[Mr_Moggie]

Just became aware of a new noise. When driving there is a faint but steady rhythmic sound, best way I can describe is a kind of "wup-wup-wup-wup". It sounds a little like a worn wheel bearing not as deep. When you slip out of gear and coast the noise stops. Most evident when accelerating in top gear. So evidently it is somewhere in the drive train. Anyone have an idea what this could be? There is no vibration associated with it.

It might be the oil level in the gear box, have you had a check? Generally the engine does the same thing when it's low on oil (by making unnatural sounds like squeaking). If not, get a Haynes Manual for the Morris Minor or read one if you have one - it's very helpful and I used it when my Moggie had issues.

Good luck and I hope things go well .

[David53]

Thanks but gearbox level is full Fairly confident it's the Uni joints. Will replace them and we'll see